Floating roof for sewage digesting apparatus



Dec. 22, 1953 J. H. WIGGINS ET AL 2,663,453

FLOATING ROOF FOR SEWAGE DIGESTING APPARATUS Filed Aug. 31, 1950 l NVEA/ TORS JOHN H W/asuvs JOHN W ALLEN ATTORNEY.

Patented Dec. 22, 1953 FLOATING ROOF FOR SEWAGE DIGESTING APPARATUS JohnH. Wiggins and John W. Allen, Chicago, 111.; said Allen assignor to saidWiggins Application August 31, 1950, Serial No. 182,444

4 Claims.

This application is a continuation-in-part of our joint application forpatent Serial No. 123,762, filed October 26, 1949, for Sewage DigestingApparatus, which resulted in U. S. Patent 2,605,014, dated July 29,1952.

Our said application discloses a sewage digesting apparatus, whosefloating cover comprises a gas collecting chamber, a flexible deckportion extending radially from said gas collecting chamber, and anannular-shaped load member formed from a relatively heavy, moldablematerial attached to the peripheral edge of said flexible deck portionso as to maintain same in such a position as to induce the flow of gaseson the underside of said cover, into said gas collecting chamber.

The main object of our present invention is to reduce the amount ofmetal used in the peripheral portion of a floating cover for sewagedisposal apparatus, that embodies the basic idea of the floating coverdisclosed in our above men tioned ending application for patent.

Another object is to reduce the cost and simplify the operation ofbuilding such a floating cover.

The figure of the drawing is a fragmentary, vertical, transversesectional view of a floating cover embodying one form of our presentinvention.

In the drawings, the reference character A designates the side Wall ofthe tank of the apparatus that holds the sewage or other liquid beingprocessed, B designates the gas collecting chamber at the center of thefloating cover that is adapted to receive gases evolved from the sewage,C designates the flexible deck portion of the cover that extendsradially from said gas collecting chamber, and D designates theannularshaped load member, made of concrete or other moldable material,that is attached to the periphery of said deck portion C, so as tomaintain the same in an inclined position, sloping upwardly from itsouter edge towards the center of the cover, and thus induce a flow ofgases on the underside of the cover into the gas collecting chamber B.In such a structure part of the weight of the load member I) issupported by its own submersion in the liquid on which the cover floats,and the remainder of the weight of the load member is supported by extrasubmersion of the deck portion C. Said deck portion would normally sinkin the liquid only as much as required by its own weight. However, theload member causes said deck portion to sink an extra amount. It is thisextra submersion above referred to.

In the form of our invention herein illustrated which is particularlyadapted for use in tanks of relatively great diameter, the centralportion of the cover is formed by a rigid, circular pontoon E? of anypreferred construction, rovided with an annular rim i, to the lower edgeof which the flexible deck portion C is rigidly attached. The gascollecting chamber B is formed by a vertically-disposed, tubular member2 at the center of the pontoon E, closed at its upper end by a gas-tightclosure 3 and having its lower end open, so as to permit the gases onthe underside of the cover to flow freely into the gas collectingchamber. Gases are conducted from the chamber B to the atmosphere, or toa point where they are used, by an eduction pipe 4 leading away fromsaid chamber. At the outer edge of the deck portion C there is a singlerelatively high or deep, annular, steel rim F, which is connected to thelateral edge of said deck portion by a liquidtight joint, said rim beingprovided at' its upper end with a flange 5. In addition to impartingstiifness to the peripheral portion of the cover, said rim supports orcarries the load member D and co-acts with same to produce a rigid,annular girder of relatively great weight, that is attached to theperipheral edge of the flexible deck portion C, and said rim F alsoeffectively prevents any liquid in the tank from getting onto the topside of said deck portion. Preferably, said load member is cast ormolded in situ around the outer side of the rim F and is permanentlyattached to same by devices on the exterior of said rim that areembedded in the concrete or other similar material of which the loadmember is constructed, during the operation of casting or molding saidmember. Thus, as shown in Figure 1, the rim F can be provided withanchoring devices 6 that are embedded in the side face of the loadmember contacted by the rim, and can also be provided withradially-disposed ties or hangers extending downwardly and outwardlyfrom the upper end portion of the rim and embedded in the top surface ofthe load member, said ties or hangers '2 taking up tension orcompression stresses to which the load member is subjected, in additionto functioning as tie bars between the flanged upper portion of the rimF and. the peripheral portion of the load member D. In casting orshaping the load member, the rim F constitutes one side wall of the forminto which the concrete is poured, and the bottom and other side wall ofsaid form are constructed in the usual manner from lumber or removableform sections that are dismantled after the concrete has set. Byconstructing the peripheral portion of the floating cover in the mannerabove described, we effect a considerable saving in steel, as only asingle annular steel member, to wit, the rim F, is combined with themolded or cast load member D.

When the cover is not floating on the sewage or other liquid-aim thetank of'the. apparatus, as shown in dotted lines, any suitable-means maybe used to support said cover. We have herein illustrated a supportingmeans for the centrali portion of the cover consistingoiasupportingstructure G located at the center ofthe and resting on the bottom ofsame, and a supporting means for the peripheralzportiorrzofathe cover,composed of chains 8 fastened tmthe upper end of the side wall A of thetank.and attached to.

the load member D by bars or rods Hat'the lower ends of said chainsembedded in the load member...

Rain water or the like that collects on the top sideof-the deckportion-C can be conducted away from same-invarious ways, as; forexample,- by one or'more :drains i (i, as. shown in thedraw ing .1-

Having thus described our. invention, what we claim and I desire to.secure by- Letters Patent. is:

1. An apparatus; comprising a tank. that is adapted tohold aliquidor-liquid-likeasubstance that 'isbeing'stored or processed,: afloating cover for said tank comprising a I gas collecting; chame ber'at approximately the center of said cover having provision forpermitting gases on theundersideof the-cover to-flow-i-nto said'chamber,a. flexible deck portion.- extending radially from saidgascollectingchamber, a single, annularshaped: metal rim. projecting: upwardly at theperipheryiofsaiddeck portion and joined to the peripheral edger-10fsameby a'liquid-tight joint; andan' annular-shaped load memberconstructed of concreteorthe like, cast'or-moldedin situon the outer.face of: said and: interlocked with same: so as: to maintainsaid deckportion an inclined position-1 sloping:v upwardly; and inwardly towardsthecenterof thereof, .saidlload member being:v located outside of. orbeyond said. rim, whereby 'partof the weight of said:load.:member issupportedby'its own-submersion in th'e'liquid on which the-cover floats.

2; An apparatus, comprising; atank that is adapted to hold a liquid orliquid-dike substance that is'being stored'onprocessed, ,a floating.;cover for said tank comprising agas-colleetingichamber atapproximatelyythecenter of saidcover'. having provision for permitting.gases on the underside of the-cover to flow into said chamber,a'flexible deck portion extending radially from said gas collectingchamber, an annular-shaped metal rim projecting upwardly from theperipheral edge of said deck portion, and an annular-shaped load member,constructed of concrete or the like, attached to the outer side of saidrim so as to maintainsaid deck portion inzsuchar position as to inducethe flow of gases on-the underside of the deck portion into said gascollecting chamber, said load mbember being located outside of or beyondsaid rim, whereby part of the weight of saidload member'is supported byits own submersion in the liquid on which the cover floats.

3 An; apparatus; comprising a tank that is adaptedito-hoid a liquid orliquid-like substance that is being stored or processed, a floatingcover for 'saidtank'comprising a gas collecting chamberatrapp'roximately the center of said cover having provision forpermitting gases on the underside of theucover. to. flowiinto saidchamber, -a flexible deokportion extending radially from said gascollectingchamber, an annular-shapedmetalrim projectingupwardly. fromthe peripheral edge. of said deck portion,.and'a 1oad..member of conicrete. or. thalike. combined with. said.rim,..for maintaining said deckportion inan inclinediposition sloping upwardly. and. inwardly towardsthe center of the rooflfsaidload member being dis posed'in suchrelationshipv with said rim tliatlpart of the weight .of saidload'memberis supportedby its own submersion. in.the.liquid on which.the cover floats.

4. An apparatus of the .kinddscribed in claim 3,.which includesinclinedtie members. extend; ing downwardly and'outwardly 'fromtheupper endportion of. said. rim and having their. lower end portions embedded-insaid load member;

JOHN'H. WIGGINS. JOHN W? ALLEN,

References" Cited in? the file of this" patent UNITED STATES PATEN'IS-vNumber Name Date 1,717,100 Downes June 11, 1&29 1,919,634' Hauptcta-L lJuly- 25,- 1933 2,129,266 Fisher et a1: Sept 6; 1938 2 ,201,652 Joor aMay'21, 1940 2,202,772 Durdin May 28g' 1940 2,289,9I3 Jo'or' July 'll,1942 2,430,592 Wiggins Nov; 111.1947 2,49 7 ,04? Prager et' al Feb. 7,1950

